Symptom Related Diagnostic Procedures

Accessory drive belt noise is most noticeable at idle. Various other drive system components (tensioner, A/C compressor, generator) may appear to be the cause of the noise which is the result of the belt. For vehicles that exhibit this condition. The service belt can be easily identified by a six inch orange band along its outside perimeter. This belt is not used in production. Before replacing the belt to resolve a noise condition, inspect all of the pulleys in the accessory drive system for misalignment. This can be accomplished by observing the various pulleys with the engine running. Runout or wobble will identify pulleys requiring attention. Observe particularly the crankshaft and coolant pump pulleys for runout that may be induced by loose pulley fasteners. Once alignment of the belt drive system is confirmed, the service belt should be installed and the noise re-evaluated even if replacement of other components appears to be required. Frequently, a belt tensioner which appears excessively "jumpy" can be fixed by belt replacement only. This is also true for belt noise which appears only with the A/C compressor engaged. If belt replacement fails to correct the condition, continue diagnosis of accessory components. Special tool J 36312 serpentine belt assortment kit is available to aid accessory noise diagnosis by providing a series of belts designed to allow engine operation with each of the belt-driven accessories eliminated in turn.